VCSEL IR power arrays allow tailored heating of a work piece by offering a tailored illumination pattern through a proper arrangement of the array. In specific applications e.g. when trying to create a very homogeneous illumination by projecting a superposition of magnified near-field images, a very accurate alignment (<5-10 μm) of the emission windows of the VCSEL chips with respect to each other is required. It is known that this high alignment accuracy when assembling the VSEL chips on a sub-mount can be achieved by performing active optical alignment. In this active optical alignment the lasers are activated and the emission is monitored by a camera during manipulation and placement of the chips. This is an expensive and time consuming method.